Systems and methods for control of steerable devices

ABSTRACT

Systems and methods for controlling an elongate device are provided herein. In some embodiments, a robotic system may comprise a manipulator assembly configured to drive an elongate device and a control device configured to receive user input commanding the elongate device. The robotic system may also comprise a control system communicatively coupled to the manipulator assembly and the control device. The control system may be configured to monitor movement of the elongate device during a plurality of intervals, monitor user input received by the control device during the plurality of intervals, and adjust a property of the elongate device based on at least one of the monitored movement or the monitored user input.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application62/741,338 filed Oct. 4, 2018, which is incorporated by reference hereinin its entirety.

FIELD

Examples described herein relate to systems and methods for a procedure,such as systems and methods for controlling elongate devices.

BACKGROUND

Instruments can be used to manipulate and perform tasks in a work space.Such instruments may be configured to be supported and operatedpartially or entirely by manipulator assemblies. Such instruments andmanipulator assemblies can be used to perform non-medical procedures ormedical procedures. For example, medical tools or medical manipulatorscan be used to perform minimally invasive medical procedures. As anotherexample, industrial tools or industrial manipulators can be used inmanufacture or testing. As yet other examples, tools or manipulators canbe used in procedures for entertainment, exploration, and various otherpurposes.

Minimally invasive medical techniques may generally be intended toreduce the amount of tissue that is damaged during invasive medicalprocedures, thereby reducing patient recovery time, discomfort, andharmful side effects. Such minimally invasive techniques may beperformed through natural orifices in a patient anatomy or through oneor more incisions. Through these natural orifices or incisions,clinicians may insert medical tools to reach a target tissue location.Minimally invasive medical tools include instruments such as therapeuticinstruments, diagnostic instruments, and surgical instruments. Minimallyinvasive medical tools may also include imaging instruments such asendoscopic instruments that provide a user with a field of view withinthe patient anatomy.

Some medical and non-medical instruments (including manipulationinstruments, imaging instruments or other sensing instruments, etc.) maybe teleoperated or otherwise computer-assisted. When performing aprocedure with a system using such an instrument, mechanisms are desiredto control properties of the instrument, such as rigidity, in responseto motion for the safety of the patient and/or the surroundingenvironment.

SUMMARY

The following presents a simplified summary of various examplesdescribed herein and is not intended to identify key or criticalelements or to delineate the scope of the claims.

In one example, a robotic system may comprise a manipulator assemblyconfigured to drive an elongate device and a control device configuredto receive user input commanding the elongate device. The robotic systemmay also comprise a control system communicatively coupled to themanipulator assembly and the control device. The control system may beconfigured to monitor movement of the elongate device during a pluralityof intervals, monitor user input received by the control device duringthe plurality of intervals, and adjust a property of the elongate devicebased on at least one of the monitored movement or the monitored userinput. Adjustment of the property may include keeping the property ofthe elongate device substantially the same during the first interval,based on at least one of movement or user input during a first intervalof the plurality of intervals. Adjustment of the property may includeadjusting the property of the elongate device at a first rate during thesecond interval, based on at least one of movement or user input duringa second interval of the plurality of intervals. Adjustment of theproperty may include adjusting the property of the elongate device at asecond rate that is greater than the first rate during the thirdinterval, based on at least one of movement or user input during a thirdinterval of the plurality of intervals.

In another example, a method may include monitoring movement of anelongate device, receiving user input commanding motion of the elongatedevice, determining a mode of operation based on at least one of themonitored movement or the received user input, and adjusting a propertyof the elongate device based on a profile associated with the mode ofoperation. Adjusting the property of the elongate device may includemaintaining the property of the elongate device substantially the sameduring a first interval, adjusting the property of the elongate deviceat a first rate during a second interval, and adjusting the property ofthe elongate device at a second rate that is different from the firstrate during a third interval.

It is to be understood that both the foregoing general description andthe following detailed description are illustrative and explanatory innature and are intended to provide an understanding of the presentdisclosure without limiting the scope of the present disclosure. In thatregard, additional aspects, features, and advantages of the presentdisclosure will be apparent to one skilled in the art from the followingdetailed description. dr

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a simplified diagram of a medical system according to someembodiments.

FIGS. 2A and 2B are simplified diagrams of side views of a patientcoordinate space including a medical instrument mounted on an insertionassembly according to some embodiments.

FIG. 3 is a flowchart illustrating a method of controlling an elongatedevice using a retraction mode according to some embodiments.

FIGS. 4A-4F are simplified diagrams of a robotic medical systemincluding a steerable elongate device at various points during a methodaccording to some embodiments.

FIG. 5 is a flowchart illustrating a method of controlling an elongatedevice using an active mode according to some embodiments.

Embodiments of the present disclosure and their advantages are bestunderstood by referring to the detailed description that follows. Itshould be appreciated that like reference numerals are used to identifylike elements illustrated in one or more of the figures, whereinshowings therein are for purposes of illustrating embodiments of thepresent disclosure and not for purposes of limiting the same.

DETAILED DESCRIPTION

The systems and techniques of the present application may providesafeguards for steerable instruments of a robotic system by monitoringmovement, user input, and/or other factors and adjusting properties,such as rigidity, of the steerable instrument in response to themonitored factors. In some examples, the robotic system may monitorphysical movement of the steerable instrument and user inputs commandingmotion of the steerable instrument. When the movement and/or user inputindicate that the steerable instrument is in a retraction mode, thesystem may reduce the rigidity of the instrument. The system mayprioritize some factors over others so that actual physical retractionof the instrument might override user input or so that user inputindicating retraction might override user input commanding steering ofthe instrument. The amount that the rigidity is affected, the rate ofchange in rigidity, and/or other aspects of the response may bedetermined according to one or more profiles associated with themonitored factors.

These examples are non-limiting, and other examples are described indetail below. Various aspects of the disclosed technology are describedwith respect to an example flexible robotic device or system, such as arobotically controlled catheter described with respect to FIGS. 1, 2A,and 2B. The disclosed technology for instrument control as describedwith respect to FIGS. 3-5 can be implemented to provide a number ofadvantages including improved safety of the patient and the surroundingenvironment in which the instrument is deployed.

FIG. 1 is a simplified diagram of a robotic medical system 100 accordingto some embodiments. In some embodiments, medical system 100 may besuitable for use in, for example, surgical, diagnostic, therapeutic, orbiopsy procedures. While some embodiments are provided herein withrespect to such procedures, any reference to medical or surgicalinstruments and medical or surgical methods is non-limiting. Thesystems, instruments, and methods described herein may be used inrobotic systems for animals, human cadavers, animal cadavers, portionsof human or animal anatomy, non-surgical diagnosis, as well as forindustrial systems and/or other general robotic systems.

As shown in FIG. 1, medical system 100 may include a manipulatorassembly 102 for operating a medical instrument 104 in performingvarious procedures on a patient P. Medical instrument 104 may extendinto an internal site within the body of patient P via an opening in thebody of patient P. The manipulator assembly 102 may be teleoperated,non-teleoperated, or a hybrid teleoperated and non-teleoperated assemblywith select degrees of freedom of motion that may be motorized and/orteleoperated and select degrees of freedom of motion that may benon-motorized and/or non-teleoperated. Manipulator assembly 102 may bemounted to and/or positioned near an operating table T. A masterassembly 106 allows an operator O (e.g., a surgeon, a clinician, or aphysician as illustrated in FIG. 1) to view the interventional site andto control manipulator assembly 102.

Master assembly 106 may be located at an operator console which is maybe located in the same room as operating table T, such as at the side ofa surgical table on which patient P is located. However, it should beunderstood that operator O can be located in a different room or acompletely different building from patient P. Master assembly 106generally includes one or more control devices for controllingmanipulator assembly 102. The control devices may include any number ofa variety of input devices, such as joysticks, trackballs, scrollwheels, directional pads, buttons, data gloves, trigger-guns,hand-operated controllers, voice recognition devices, body motion orpresence sensors, and/or the like.

Manipulator assembly 102 supports medical instrument 104 and may includea kinematic structure of one or more non-servo controlled links (e.g.,one or more links that may be manually positioned and locked in place,generally referred to as a set-up structure), one or more servocontrolled links (e.g., one or more links that may be controlled inresponse to commands from the control system), and/or a manipulator.Manipulator assembly 102 may include a plurality of actuators or motorsthat drive inputs on medical instrument 104 in response to commands fromthe control system (e.g., a control system 112). The actuators mayinclude drive systems that when coupled to medical instrument 104 mayadvance medical instrument 104 into a naturally or surgically createdanatomic orifice. Other drive systems may move the distal portion ofmedical instrument 104 in multiple degrees of freedom, which may includethree degrees of linear motion (e.g., linear motion along the X, Y, ZCartesian axes) and in three degrees of rotational motion (e.g.,rotation about the X, Y, Z Cartesian axes). Additionally, the actuatorscan be used to actuate an articulable end effector of medical instrument104 for grasping tissue in the jaws of a biopsy device and/or the like.

Medical system 100 may include a sensor system 108 with one or moresub-systems for receiving information about the manipulator assembly 102and/or the medical instrument 104. Such sub-systems may include aposition/location sensor system (e.g., an electromagnetic (EM) sensorsystem); a shape sensor system for determining the position,orientation, speed, velocity, pose, and/or shape of a distal portionand/or of one or more segments along a flexible body that may make upmedical instrument 104; a visualization system for capturing images fromthe distal portion of medical instrument 104; and/or actuator positionsensors such as resolvers, encoders, potentiometers, and the like thatdescribe the rotation and orientation of the motors controlling theinstrument 104.

Medical system 100 may include a display system 110 for displaying animage or representation of the surgical site and medical instrument 104.In some examples, display system 110 may present pre-operative orintra-operative images of a surgical site using image modalities suchas, computed tomography (CT), magnetic resonance imaging (MRI),fluoroscopy, thermography, ultrasound, optical coherence tomography(OCT), thermal imaging, impedance imaging, laser imaging, nanotube X-rayimaging, and/or the like. In some embodiments, medical instrument 104may include a visualization system that includes an image captureassembly to record a concurrent or real-time image of a surgical siteand to provide the image to the operator O through one or more displaysof display system 110.

In some examples, medical system 100 may configure the displayedrepresentations, the medical instrument 104, and the controls of masterassembly 106 such that the relative positions of the medical instrumentsare similar to the relative positions of the eyes and/or hands ofoperator O. In this manner, operator O can manipulate medical instrument104 and hand controls as if viewing the workspace in substantially truepresence.

In some examples, such as for purposes of image-guided medicalprocedures, display system 110 may display a virtual navigational imagein which the actual location of medical instrument 104 is registered(e.g., dynamically referenced) with the preoperative or concurrentimages/model. This may be done to present the operator O with a virtualimage of the internal surgical site from a viewpoint of medicalinstrument 104.

Medical system 100 may also include control system 112. Control system112 includes at least one memory and at least one computer processor(not shown) for effecting control between manipulator assembly 102,medical instrument 104, master assembly 106, sensor system 108, and/ordisplay system 110. Control system 112 also includes programmedinstructions (e.g., a non-transitory machine-readable medium storing theinstructions) to implement some or all of the methods described inaccordance with aspects disclosed herein, including instructions forproviding information to display system 110. While control system 112 isshown as a single block in the simplified schematic of FIG. 1, thesystem may include two or more data processing circuits with one portionof the processing optionally being performed on or adjacent tomanipulator assembly 102, another portion of the processing beingperformed at master assembly 106, and/or the like. The processors ofcontrol system 112 may execute instructions corresponding to processesdisclosed herein and described in more detail below.

In some examples, control system 112 may receive force and/or torquefeedback from medical instrument 104. Responsive to the feedback,control system 112 may transmit signals to master assembly 106. In someexamples, control system 112 may transmit signals instructing one ormore actuators of manipulator assembly 102 to move medical instrument104.

Control system 112 may obtain sensor data from sensor system 108 that isused to compute an approximate location of medical instrument 104 withrespect to the anatomy of patient P. The system may implement the sensorsystem 108 to register and display the medical instrument together withpreoperatively or intraoperatively recorded medical images. For example,PCT Publication WO 2016/191298 (published Dec. 1, 2016 and titled“Systems and Methods of Registration for Image Guided Surgery”), whichis incorporated by reference herein in its entirety, discloses examplesystems.

Medical system 100 may further include operations and support systemssuch as illumination systems, articulation (e.g., steering) controlsystems, irrigation systems, and/or suction systems (not shown). In someembodiments, medical system 100 may include more than one manipulatorassembly and/or more than one master assembly. The exact number ofmanipulator assemblies may depend on the medical procedure and spaceconstraints within the operating room, among other factors. Masterassembly 106 may be co-located or they may be positioned in separatelocations. Multiple master assemblies may allow more than one operatorto control one or more manipulator assemblies in various combinations.

FIGS. 2A and 2B are simplified diagrams of side views of a patientcoordinate space including a medical instrument mounted on an insertionassembly according to some embodiments. As shown in FIGS. 2A and 2B, asurgical environment 300 may include a patient P positioned on a tableT. Patient P may be stationary within the surgical environment 300 inthe sense that gross patient movement is limited by sedation, restraint,and/or other means. Cyclic anatomic motion including respiration andcardiac motion of patient P may continue. Within surgical environment300, a medical instrument 304 is used to perform a medical procedurewhich may include, for example, surgery, biopsy, ablation, illumination,irrigation, suction, or a system registration procedure. The medicalinstrument 304 may be, for example, the instrument 104. The instrument304 includes a flexible elongate device 310 (e.g., a catheter) coupledto an instrument body 312. Elongate device 310 includes one or morechannels (not shown) sized and shaped to receive a medical tool (notshown).

Elongate device 310 may also include one or more sensors (e.g.,components of the sensor system 108). In some examples, an articulationsensor 314, such as a fiber optic shape sensor, may be fixed at aproximal point 316 on instrument body 312. The proximal point 316 of thearticulation sensor 314 may be movable with instrument body 312, and thelocation of the proximal point 316 may be known (e.g., via a trackingsensor or other tracking device). Articulation sensor 314 may measure ashape from the proximal point 316 to another point, such as distalportion 318 of the elongate device 310. Articulation sensor 314 may bealigned with the flexible elongate device 310 (e.g., provided within aninterior channel (not shown) or mounted externally). In some examples,the optical fiber may have a diameter of approximately 200 μm. In otherexamples, the diameter may be larger or smaller. The articulation sensor314 may be used to determine the shape of flexible elongate device 310.Optical fibers including Fiber Bragg Gratings (FBGs) may be used toprovide strain measurements in structures in one or more dimensions.Various systems and methods for monitoring the shape and relativeposition of an optical fiber in three dimensions are described in U.S.patent application Ser. No. 11/180,389 (filed Jul. 13, 2005 and titled“Fiber optic position and shape sensing device and method relatingthereto”); U.S. patent application Ser. No. 12/047,056 (filed on Jul.16, 2004 and titled “Fiber-optic shape and relative position sensing”);and U.S. Pat. No. 6,389,187 (filed on Jun. 17, 1998 and titled “OpticalFibre Bend Sensor”), which are all incorporated by reference herein intheir entireties. Sensors in some embodiments may employ other suitablestrain sensing techniques, such as Rayleigh scattering, Ramanscattering, Brillouin scattering, and Fluorescence scattering. Varioussystems for using fiber optic sensors to register and display a surgicalinstrument with surgical images are provided in PCT Publication WO2016/191298 (published Dec. 1, 2016 and titled “Systems and Methods ofRegistration for Image Guided Surgery”), which is incorporated byreference herein in its entirety.

In some examples, position sensors such as electromagnetic (EM) sensors,may be incorporated into the medical instrument 304. A series ofposition sensors may be positioned along the flexible elongate device310 and used for shape sensing. In some examples, position sensors maybe configured and positioned to measure six degrees of freedom, e.g.,three position coordinates X, Y, Z and three orientation anglesindicating pitch, yaw, and roll of a base point. In some examples,position sensors may be configured and positioned to measure fivedegrees of freedom, e.g., three position coordinates X, Y, Z and twoorientation angles indicating pitch and yaw of a base point. Furtherdescription of a position sensor system is provided in U.S. Pat. No.6,380,732 (filed Aug. 11, 1999 and titled “Six-Degree of FreedomTracking System Having a Passive Transponder on the Object BeingTracked”), which is incorporated by reference herein in its entirety.

Elongate device 310 may house cables, linkages, or other steeringcontrols (not shown) that extend between instrument body 312 and distalportion 318 to controllably bend distal portion 318. In some examples,at least four cables are used to provide independent up-down steering tocontrol a pitch of distal portion 318 and left-right steering to controla yaw of distal portion 318. Steerable elongate devices are described indetail in U.S. patent application Ser. No. 13/274,208 (filed Oct. 14,2011) (disclosing “Catheter with Removable Vision Probe”), which isincorporated by reference herein in its entirety. The instrument body312 may include drive inputs that removably couple to and receive powerfrom drive elements, such as actuators, of the assembly.

Instrument body 312 may be coupled to instrument carriage 306.Instrument carriage 306 may be mounted to an insertion stage 308 fixedwithin the surgical environment 300. Alternatively, insertion stage 308may be movable but have a known location (e.g., via a tracking sensor orother tracking device) within surgical environment 300. Instrumentcarriage 306 may be a component of a manipulator assembly (e.g.,manipulator assembly 102) that couples to medical instrument 304 tocontrol insertion motion (e.g., motion along the A axis) and/or motionof the distal portion 318 of the elongate device 310 in multipledirections such as yaw, pitch, and/or roll. Instrument carriage 306 orinsertion stage 308 may include actuators, such as servomotors, (notshown) that control motion of instrument carriage 306 along insertionstage 308.

A sensor device 320, which may be a component of the sensor system 108,may provide information about the position of instrument body 312 as itmoves on insertion stage 308 along an insertion axis A. Sensor device320 may include one or more resolvers, encoders, potentiometers, and/orother sensors that determine the rotation and/or orientation of theactuators controlling the motion of instrument carriage 306 andconsequently the motion of instrument body 312. In some embodiments,insertion stage 308 is linear. In some embodiments, insertion stage 308may be curved or have a combination of curved and linear sections.

FIG. 2A shows the instrument body 312 and the instrument carriage 306 ina retracted position along insertion stage 308. In this retractedposition, the proximal point 316 is at a position L₀ on axis A. In FIG.2B, instrument body 312 and instrument carriage 306 have advanced alongthe linear track of insertion stage 308, and the distal portion 318 ofelongate device 310 has advanced into patient P. In this advancedposition, the proximal point 316 is at a position L₁ on the axis A. Insome examples, encoder and/or other position data from one or moreactuators controlling movement of instrument carriage 306 alonginsertion stage 308 and/or one or more position sensors associated withinstrument carriage 306 and/or insertion stage 308 may be used todetermine the position of proximal point 316 relative to position L₀. Insome examples, this position may further be used as an indicator of thedistance or insertion depth to which distal portion 318 of elongatedevice 310 is inserted into the passageway(s) of the anatomy of patientP.

As the elongate device 310 is advanced and retracted in the passageways,properties of the elongate device 310—such as the radial or axialrigidity (e.g., stiffness) of the elongate device 310—may be altered inorder to facilitate movement and protect the passageways. For example,the rigidity of the distal portion 318 of the elongate device 310 may beincreased when the device is advanced through a passageway to guide thedevice, to anchor the device in place, or to manipulate a deformablepassageway. In contrast, the rigidity of the distal portion 318 of theelongate device 310 may be decreased when the device is retracted toreduce the force on the passageways, which may otherwise lead toabrasion or injury. In the course of a procedure, retraction may includelarge-scale movement as well as minor position adjustments and smallreciprocal motions. Different types of movements may benefit fromdifferent rates and degrees of change in rigidity of the elongate device310. For example, smaller movements may benefit from relatively smallerand slower changes in rigidity to avoid unexpected changes in theorientation of the distal portion of the elongate device 310.Accordingly, in the following examples, a system may adjust rigidity orother properties of the flexible elongate device 310, which may beperformed repeatedly during the course of a procedure.

Retraction of the elongate device 310 is described first, and examplesof advancing the elongate device 310 follow. FIGS. 3 and 4A-4Fillustrate an elongate device 310 of a robotic medical system beingretracted and the system reducing the rigidity of the elongate device310 accordingly. FIG. 3 is a flowchart describing a method 350 ofcontrolling an elongate device in a retraction mode according to someembodiments. The method 350 is illustrated in FIG. 3 as a set ofoperations or processes. The processes illustrated in FIG. 3 may beperformed in a different order than the order shown in FIG. 3, and oneor more of the illustrated processes might not be performed in someembodiments of method 350. Additionally, one or more processes that arenot expressly illustrated in FIG. 3 may be included before, after, inbetween, or as part of the illustrated processes. The method may beperformed by a system—such as the robotic medical system 100 describedabove—and in some embodiments, one or more of the processes of method350 may be implemented, at least in part, in the form of executable codestored on non-transitory, tangible, machine-readable media that, whenrun by one or more processors (e.g., the processors of the controlsystem 112 above) of the system, may cause the one or more processors toperform one or more of the processes. FIGS. 4A-4F are simplifieddiagrams of the robotic medical system 100 including the steerableelongate device 310 at various points during the method 350 according tosome embodiments.

Referring to process 352 of FIG. 3, in some examples, an elongate device(e.g., the elongate device 310 as shown in FIG. 4A) may be introducedinto a passageway, such as an anatomic passageway. Example anatomicpassageways may include portions of the intestines, the kidneys, thebrain, the heart, the circulatory system, lungs, urethras, arteries,umbilical lines, and/or the like.

Referring to process 354, the control system 112 of the robotic system100 may monitor physical movement of the elongate device 310. Monitoringmay occur continuously, periodically, and/or at set times. Accordingly,process 354 may be performed concurrently with other processes in method350.

For detecting retraction, the control system 112 may monitor theposition of any number of points on the elongate device 310 (e.g., apoint 402, a proximal point along the elongate device, a distal pointalong the elongate device, etc.), on a body to which the device iscoupled, and/or on an instrument extending through the elongate device.The control system 112 may capture the position of each of these pointsin order to detect retraction from a latched position represented by amarker 404, as described further below. The positions may be measured bya sensor system—such as sensor system 108—using any suitable set ofsensors including position sensors, shape sensors—such as shape sensor314—and/or other suitable position measuring devices. For example andwith reference to FIG. 2A-B, a sensor device 320 may be used to measuremovement of an instrument body 312 as the instrument body 312 moves onan insertion stage 308 along an insertion axis A. The system may use thesensor device 320 to monitor changes in the insertion depth of theelongate device. Additionally or in the alternative, monitoring mayinclude measuring positions or forces supplied by one or more actuatorscoupled to cables, linkages, pull wires, tendons, or other steeringcontrols within the elongate device and used to steer the elongatedevice.

Monitoring movement of the elongate device may also include monitoringvelocity of one or more points on the elongate device 310, such as point402. For example, the system may record position measurements over timewith which to calculate the amount of movement and/or the velocity. Thesystem may also monitor and record other state properties in the courseof monitoring, such as current time and/or a current controlconfiguration (e.g., current rigidity caused by closed-loop steeringwire control) of the elongate device. Where the control configurationrelates to an adjustable property of the elongate device, such asrigidity, the system may consider previous adjustments made to theproperty to determine present values.

Referring to process 356 of FIG. 3, the control system 112 may monitorcontrol devices that an operator O may use to control the elongatedevice 310. These control devices may include the control devices of themaster assembly 106, and in various examples, the control devices mayinclude a joystick, a trackball, a scroll wheel, a directional pad, abutton, a data glove, a trigger-gun, a hand-operated controller, a voicerecognition device, a body motion or presence sensor, and/or othersuitable control device. The monitoring of process 356 may be performedconcurrently with other processes in method 350. For example, in thecourse of monitoring, the control system 112 may receive a user inputthat instructs the system to move the elongate device along an insertionaxis A and/or user input that instructs the system to articulate theelongate device to steer it in a degree of freedom other than along theinsertion axis.

Referring to process 358, the control system 112 may determine a mode ofoperation based on the physical movement monitored in process 354, theuser input received in process 356, and/or other suitable factors. Inthe examples that follow, the elongate device 310 may have an activemode and a retraction mode of operation, and the determination mayidentify the retraction mode. Further examples where the determinationidentifies the active mode are described with reference to a subsequentfigure.

The control system 112 may determine the retraction mode based on thephysical movement of the elongate device (e.g., as monitored in process354) and/or the user input (e.g., as monitored in process 356). Withrespect to physical movement, the control system 112 may determine theretraction mode of operation based on a reference point 402 of theelongate device 310 being retracting more than a threshold distance(e.g., 5 mm, 10 mm, etc.) from a position (e.g., a latched position 404,which may be recorded at the conclusion of the most recent forwardmotion). In some examples, the control system 112 may determine theretraction mode of operation based on a retraction velocity of theelongate device 310 exceeding a threshold velocity (e.g., 0.1 mm/s, 5mm/s, etc.). In some examples, the control system 112 may determine theretraction mode of operation based on the reference point 402 retractingfor an amount of time that exceeds a threshold time (e.g., 1 second, 10seconds, etc.). The threshold distance, threshold velocity, or thresholdtime may be predetermined thresholds.

In some examples, the control system 112 may take into accountperturbations, sensed noise, cyclic anatomic motion (e.g., respirationand cardiac motion), movement within an anatomy, other movement causedby environmental displacement, and/or combinations thereof. In someembodiments, these external effects may be filtered from the monitoreddata to isolate physical movement of the elongate device relative to thepassageway. This may allow the amount of advancement or retraction to bemeasured even if the patient moves. Furthermore, in some embodiments,these external effects may themselves trigger a response from thesystem, even if there is no relative movement of the elongate devicerelative to the passageway. For example, the control system 112 mayselect the retraction mode of operation when a cough, spasm, or othermovement of the patient is detected, even if the elongate device doesnot move relative to the patient.

With respect to determining a mode of operation based on user input, thecontrol system 112 may select the retraction mode of operation based onany suitable aspect of the user input of process 356. In some examples,the system may determine the retraction mode based on user inputcommanding motion in the retracting direction at a velocity greater thana threshold velocity (e.g., 0.1 mm/s, 5 mm/s, etc.). In some examples,the system may determine the retraction mode based on user inputcommanding motion in the retracting direction for longer than athreshold time (e.g., 1 second, 10 seconds, etc.). The thresholdvelocity or threshold time may be predetermined thresholds. In someexamples, the system may determine the retraction mode of operationbased on the amount of pressure placed on an input device and/or loss ofcontact between the operator's hand and the input device.

Where the user input(s) command motion in more than one degree offreedom, the degrees of freedom may be prioritized. In some examples,priorities may be based on patient safety. For example, a first userinput that commands a retracting motion may have priority over a seconduser input that commands a steering motion so that the system selectsthe retraction mode based on the retracting motion regardless of anysteering motion. This may avoid forcing a flexed elongate device backthrough the passageway. In some such examples, the first user input thatcommands a retraction motion may be given priority over the second userinput that commands steering if the size, speed, and/or velocity of thefirst input exceeds a threshold. Accordingly, the system may select theretraction mode based on the retracting motion of the first user inputregardless of any steering motion if the first user input exceeds thethreshold.

Where the monitored motion of process 354 and the user inputs of process356 conflict, the system may utilize any suitable rule or heuristic todetermine the appropriate response. In some examples, if either themotion of the elongate device or any of the user inputs satisfy any ofthe above-noted conditions for the retraction mode, the system mayselect the retraction mode regardless of the remainder of the motionand/or the input(s). This may provide a failsafe that places theelongate device in the retraction mode when there is any indication ofretraction. In some examples, the motion of the elongate device may beprioritized over the user input, so that the system selects theretraction mode if the elongate device is physically retracted, withoutconcern for the user input. This may allow for an appropriate responseif the elongate device is retracted (and, in some cases, advanced)manually by hand or by other processes.

When the elongate device transitions between modes, the system mayrecord state properties such as position, time, control configuration,etc. As a change from active mode to retraction mode may indicate theconclusion of the most recent forward motion, the system may record thepositions of the reference point(s) 404 when the mode changes for use inthe comparisons described above.

Referring to process 360, the control system 112 may determine anadjustment to a property—such as radial rigidity or axial rigidity—ofthe elongate device 310 based on the retraction mode of operation andone or more profiles associated with the retraction mode. The profile(s)may specify how much to adjust a property of a portion of the elongatedevice, how quickly to adjust the property, upper and/or lower boundsfor the adjustment, and/or other suitable aspects. The profile(s) may bebased on any of the considerations described in the context of process358, and the considerations that determine a mode of operation may bethe same or different from the considerations that determine how much toadjust, how quickly to adjust, etc. The system may apply any number ofprofiles for a given property and mode of the elongate device, anddifferent profiles may be used at different stages of a procedure.

In various examples, a profile may relate to rigidity and may utilizeany number of suitable factors for determining a rigidity for theelongate device 310 in the retraction mode. Illustrative factorsinclude: amount of retraction from a latched position, velocity ofretraction, duration of retraction, total insertion depth, location as apercentage of current maximum insertion depth, size of an operatorinput, speed of an operator input, velocity of an operator input,duration of an operator input, and/or pressure or lack thereof on aninput device. The factors may include an amount by which a referencepoint 402 of the elongate device 310, a body to which the device iscoupled, and/or an instrument extending through the elongate device isretracted from a position 404 latched at the conclusion of the mostrecent forward motion. For factors based on motion of the elongatedevice (e.g., as monitored in process 354), the system may take intoaccount perturbations, sensed noise, cyclic anatomic motion (e.g.,respiration and cardiac motion), movement within an anatomy, othermovement caused by environmental displacement, and/or combinationsthereof. The factors may also include external forces applied to theelongate device, a shape of the elongate device, sensitivity of anatomyforming a passageway, a curvature of the anatomy, an operatorpreference, and/or other suitable factors.

Where factors conflict, as in the above example, the system may utilizeany suitable rule or heuristic to determine the appropriate response. Insome examples, the factor that results in the least rigidity may govern.For example, when motion of the elongate device would produce a firstdegree of rigidity and when the first user input would produce a seconddegree of rigidity, the system may implement the lesser of the two. Insome examples, factors based on real-world motion of the elongate devicemay govern over factors based on user inputs so that the systemimplements a degree of rigidity based on the motion of the elongatedevice where there is conflict.

The profile may include any combination of linear, non-linear,exponential, logarithmic, step, piece-wise, hyperbolic, parabolic,periodic/trigonometric, inverse hyperbolic, polynomial, modular, othermonotonic functions, and/or the like that define the relationshipbetween the property (e.g., rigidity) and the factors that determine theproperty. In some embodiments, the profile may depends on derivatives,integrals, or other functions of the relevant factors. In someembodiments, the profile may have a stepwise configuration with norigidity adjustment until a threshold is met, followed by a fullslackening after the threshold is reached.

A profile may be organized into different regions of different behavior.An example profile may include a first region in which a one or more(e.g., a set of) factors have not yet exceeded a predeterminedthreshold, a second region in which the rigidity is reduced inproportion to the factor(s), and a third region in which the rigidity isreduced to a lower value (e.g., a minimum value). The minimum value maybe set at a nominal, possibly non-zero value, to retain at least somecontrol over a bend in the distal portion of the elongate device, aninstrument deployed at the distal portion of the elongate device, and/orthe like. Minimums and maximums may be determined in part by a physicallimit of the actuators, the steering controls, the elongate device, abody to which the elongate device is coupled, and/or the instrument. Insome examples, a maximum rate may be configured to avoid elasticrebound, buckling or bunching of the steering controls, or other effectsof the actuators or steering controls.

Referring to process 362, the control system 112 may adjust the propertyof the portion of the elongate device according to the adjustmentsand/or profiles as determined in process 360. The profiles may governboth the final value and the rate at which changes are made. In someexamples, the control system 112 may adjust the rigidity of a distalportion of the elongate device 310 to a value determined by the profileby adjusting forces applied by actuators to steering controls of theelongate device. In some such examples, the control system 112 mayadjust the force and/or torque applied by the actuators to control thepushing and/or pulling of one or more wires within the elongate device.When adjusting a force and/or torque applied by the actuators, thecontrol system 112 may implement a scaling factor and/or torquemultiplier used to scale a force and/or torque that is applied by theactuators. In activating the actuators, the control system 112 mayconsider an external force applied to the elongate device, a shape ofthe elongate device, the sensitivity of the anatomy forming thepassageways, the curvature of the anatomy, one or more operatorpreferences, and/or other considerations.

Referring to process 364, when the control system 112 detects a userinput in process 356, the control system 112 may control the elongatedevice in response to the user input. In some embodiments, the controlsystem 112 may cause an insertion stage to retract the elongate devicealong the insertion axis in response to the user input. In someembodiments, the control system 112 may cause actuators to apply forceto cables, linkages, pull wires, tendons, or other steering controlswithin the elongate device in response to the user input.

Some aspects of how the system controls the elongate device may bedetermined based on the property of the portion of the elongate deviceadjusted in process 362. For example, the system may change how much orhow quickly the elongate device is retracted based on the rigidity ofthe portion of the elongate device. For example, the system may set aretraction velocity limit based on the current rigidity, a rate at whichthe rigidity is currently being reduced, and/or a maximum rate at whichthe rigidity can be reduced. This may allow the system to retract theelongate device more quickly when there is little risk of injury to thepassageway. In further examples, the system changes how much or howquickly the elongate device is articulated in the other degrees offreedom based on the property adjusted in process 362.

The system 100 may perform one or more of the monitoring,determinations, adjustments, or control of processes 354-364 repeatedlythroughout the procedure to provide real-time or near real-time responsein the elongate device 310 before concluding in process 366. During aprocedure, the mode of operation for the elongate device may switchbetween a retraction mode and an active mode. As explained above andwill be explained in further detail below, the system may determine theappropriate adjustment to properties of the elongate device (e.g.,rigidity) based on the mode of operation and/or one or more profilesassociated with the mode of operation.

The method 350 will now be explained in the context of a roboticprocedure. For example, the elongate device 310 may begin in an activemode and have a certain degree of rigidity as illustrated in FIG. 4A. Asillustrated in FIG. 4B, the control system 112 may keep the elongatedevice 310 in the active mode while the elongate device 310 is retractedup until the amount of retraction (measured or user-instructed) or theretraction velocity (measured or user-instructed) reaches a threshold.In this example, the control system 112 may keep the rigidity shown inFIG. 4B the same as in FIG. 4A, although in other examples, user inputwhile in the active mode may cause changes in the rigidity. Asillustrated in FIG. 4C, the control system 112 may determine that thepoint 402 of the elongate device 310 has retracted from the latchedposition 404 by more than a threshold amount or has been instructed todo so, and the control system 112 may reduce the rigidity of theelongate device 310 at a rate according to the profile. The rate and/orfinal rigidity specified by the profile may depend on a number offactors such as the amount that the elongate device 310 has beenwithdrawn, the retraction velocity of the elongate device 310, theamount of time that the elongate device 310 has been in the retractionmode, and/or other suitable factors. For example, when the elongatedevice 310 is retracted or commanded to retract at a slower rate asshown in FIG. 4C, the rigidity may be reduced at a slower rate accordingto the profile.

Referring to FIGS. 4D-4F, when the elongate device 310 is retracted orcommanded to retract at a faster rate, the rigidity may be reduced at afaster rate according to the profile. In that regard, FIG. 4Dcorresponds to FIG. 4A and illustrates the elongate device 310 in theactive mode before retraction. FIG. 4E corresponds to FIG. 4B andillustrates the elongate device 310 in the active mode because theamount of retraction and/or the retraction velocity have not yet reachedthe respective threshold(s). FIG. 4F corresponds to FIG. 4C andillustrates the control system 112 determining that the point 402 of theelongate device 310 has retracted by more than a threshold amount or hasbeen instructed to do so. The control system 112 may reduces therigidity of the elongate device 310 at faster rate than that of FIG. 4Cdue to the faster retraction velocity (measured or user-instructed).

In some examples, if the control system 112 determines that the elongatedevice 310 is retracting or instructed to retract at an even greaterretraction velocity, the rigidity may be reduced at the greater rate(e.g., the system 100 transitions from FIG. 4D to FIG. 4F) regardless ofthe amount that the elongate device 310 has been retracted.

During the course of a procedure, processes of the method 350 may berepeated multiple times, and the states and responses illustrated inFIGS. 4A-4F may occur multiple times and in any order. For example, thecontrol system 112 may maintain the rigidity of the elongate device 310during a first time interval based on the motion and/or user input inthe first interval, reduce the rigidity of the elongate device 310 at afirst rate (e.g., as illustrated in FIG. 4C) during a second timeinterval based on the motion and/or user input in the second interval,and reduce the rigidity during a third time interval based on the motionand/or user input in the third time interval.

Some of the above examples describe operation in the retraction mode.FIG. 5 is a flowchart describing a method 500 of controlling an elongatedevice in an active mode according to some embodiments. The method 500is illustrated in FIG. 5 as a set of operations or processes. Theprocesses illustrated in FIG. 5 may be performed in a different orderthan the order shown in FIG. 5, and one or more of the illustratedprocesses might not be performed in some embodiments of method 500.Additionally, one or more processes that are not expressly illustratedin FIG. 5 may be included before, after, in between, or as part of theillustrated processes. The method may be performed by a system—such asthe robotic medical system 100 described above—and in some embodiments,one or more of the processes of method 500 may be implemented, at leastin part, in the form of executable code stored on non-transitory,tangible, machine-readable media that, when run by one or moreprocessors (e.g., the processors of the control system 112 above) of thesystem, may cause the one or more processors to perform one or more ofthe processes. The method 500 may be performed in combination withmethod 350 in an alternating fashion during the course of a procedure.

Referring to process 502, in some examples, the elongate device isintroduced into a passageway. Referring to process 504, the controlsystem 112 of the robotic system 100 may monitor physical movement ofthe elongate device, and referring to process 506, the control system112 may monitor control device(s) used to control the elongate device.Processes 504 and 506 may be performed substantially as described inprocesses 354 and 356, respectively.

Referring to process 508, the control system 112 may determine a mode ofoperation based on the physical movement of the elongate devicemonitored in process 504, the user input monitored in process 506,and/or other suitable factors. In the examples that follow, the elongatedevice 310 may have an active mode and a retraction mode or operation,and the determination may identify the active mode of operation.

Some aspects of physical movement of the elongate device 310 monitoredin process 504 that may cause the control system 112 to select theactive mode include advancing motion of the elongate device 310 as wellas some types of retracting motion. For example, the control system 112may select the active mode when the elongate device 310 retracts by lessthan a threshold amount and a retraction velocity is below a threshold.In further examples, the control system 112 may select the active modewhen the elongate device has been inert or not retracting for a periodof time.

Similarly, with respect to the user input monitored in process 506, thecontrol system 112 may select the active mode when user input commandsthe elongate device to advance or commands an amount of retraction thatis less than a threshold and a retraction velocity that is less than athreshold. The control system 112 may also consider the axis associatedwith the user input. The control system 112 may select the active modeof operation when a user input commands articulation of the elongatedevice in a degree of freedom other than along the insertion axis, e.g.,provided that the user input does not also command a retraction motiongreater than a threshold. For example, the control system 112 may selectthe active mode if the operator O attempts to steer the elongate devicewithout retracting it.

Where the monitored motion of process 504 and the user inputs of process506 conflict, the system may utilize any suitable rule or heuristic todetermine the appropriate response.

Referring to process 510, when the control system 112 detects a userinput (e.g., in process 506), the control system 112 may control theelongate device in response to the user input. In some embodiments, thecontrol system 112 may cause an insertion stage to advance or retractthe elongate device along the insertion axis in response to the userinput. In some embodiments, the control system 112 may cause actuatorsto apply force to cables, linkages, pull wires, tendons, or othersteering controls within the elongate device in response to the userinput. In contrast to the retraction mode, in the active mode, thecontrol system 112 may maintain the rigidity of the elongate device 310or increase it while controlling the elongate device in process 510.

The system 100 may perform one or more of the monitoring,determinations, adjustments, or control of processes 504-510 repeatedly,alone or in combination with one or more of the processes of method 350,before concluding in process 512. For example, during a procedure, themode of operation for the elongate device may switch between theretraction mode and the active mode, and the system may determine theappropriate adjustment to properties of the elongate device (e.g.,rigidity) based on the mode of operation and/or one or more profilesassociated with the mode of operation.

In these examples and others, the system may provide both rapid andfine-grained control of various properties of the elongate deviceincluding rigidity and may provide additional protection against damageto the passageway in which the elongate device is inserted.

Various Examples of Implementations of the Disclosure

This disclosure describes various instruments and portions ofinstruments in terms of their state in three-dimensional space. Forexample, the term position refers to the location of an object or aportion of an object in a three-dimensional space (e.g., three degreesof translational freedom along Cartesian x-, y-, and z-coordinates). Theterm orientation refers to the rotational placement of an object or aportion of an object (e.g., one or more degrees of rotational freedom,such as roll, pitch, and yaw). The term pose refers to the position ofan object or a portion of an object in at least one degree oftranslational freedom and to the orientation of that object or portionof the object in at least one degree of rotational freedom (e.g., up tosix total degrees of freedom). The term shape refers to a set of poses,positions, or orientations measured along an object.

One or more elements in embodiments of this disclosure may beimplemented in software to execute on a processor of a computer systemsuch as control processing system. When implemented in software, theelements of the embodiments of this disclosure may be code segments toperform various tasks. The program or code segments can be stored in aprocessor readable storage medium or device that may have beendownloaded by way of a computer data signal embodied in a carrier waveover a transmission medium or a communication link. The processorreadable storage device may include any medium that can storeinformation including an optical medium, semiconductor medium, and/ormagnetic medium. Processor readable storage device examples include anelectronic circuit; a semiconductor device, a semiconductor memorydevice, a read only memory (ROM), a flash memory, an erasableprogrammable read only memory (EPROM); a floppy diskette, a CD-ROM, anoptical disk, a hard disk, or other storage device. The code segmentsmay be downloaded via computer networks such as the Internet, Intranet,etc. Any of a wide variety of centralized or distributed data processingarchitectures may be employed. Programmed instructions may beimplemented as a number of separate programs or subroutines, or they maybe integrated into a number of other aspects of the systems describedherein. In some examples, the control system may support wirelesscommunication protocols such as Bluetooth, Infrared Data Association(IrDA), HomeRF, IEEE 802.11, Digital Enhanced CordlessTelecommunications (DECT), ultra-wideband (UWB), ZigBee, and WirelessTelemetry.

Medical tools may be delivered through the flexible elongate devices(e.g., catheters) disclosed herein and may include, for example, imagecapture probes, biopsy instruments, laser ablation fibers, and/or othersurgical, diagnostic, or therapeutic tools. Medical tools may includeend effectors having a single working member such as a scalpel, a bluntblade, an optical fiber, an electrode, and/or the like. Other endeffectors may include, for example, forceps, graspers, scissors, clipappliers, and/or the like. Other end effectors may further includeelectrically activated end effectors such as electrosurgical electrodes,transducers, sensors, and/or the like. Medical tools may include imagecapture probes that include a stereoscopic or monoscopic camera forcapturing images (including video images). Medical tools mayadditionally house cables, linkages, or other actuation controls thatextend between its proximal and distal portions to controllably bend thedistal portion of a medical tool. Steerable instruments are described indetail in U.S. Pat. No. 7,316,681 (filed on Oct. 4, 2005 and titled“Articulated Surgical Instrument for Performing Minimally InvasiveSurgery with Enhanced Dexterity and Sensitivity”) and U.S. patentapplication Ser. No. 12/286,644 (filed Sep. 30, 2008 and titled “PassivePreload and Capstan Drive for Surgical Instruments”), which areincorporated by reference herein in their entireties.

The systems described herein may be suited for navigation and treatmentof anatomic tissues, via natural or surgically created passageways, inany of a variety of anatomic systems, including the lung, colon,intestines, kidneys and kidney calices, brain, heart, circulatory systemincluding vasculature, and/or the like.

Note that the processes and displays presented might not inherently berelated to any particular computer or other apparatus. Variousgeneral-purpose systems may be used with programs in accordance with theteachings herein, or it may prove convenient to construct a morespecialized apparatus to perform the operations described. In addition,it will be appreciated that a variety of programming languages may beused to implement the examples described herein.

While certain examples have been described and shown in the accompanyingdrawings, it is to be understood that such examples are merelyillustrative of and are not restrictive, and that the described examplesare not limited to the specific constructions and arrangements shown anddescribed, since various other modifications may occur to thoseordinarily skilled in the art.

1. A robotic system comprising: a manipulator assembly configured todrive an elongate device; a control device configured to receive userinput commanding the elongate device; and a control systemcommunicatively coupled to the manipulator assembly and the controldevice, the control system configured to: monitor movement of theelongate device during a plurality of intervals; monitor user inputreceived by the control device during the plurality of intervals; adjusta property of the elongate device based on at least one of the monitoredmovement or the monitored user input, wherein adjustment of the propertyincludes operations to: based on at least one of movement or user inputduring a first interval of the plurality of intervals, keep the propertyof the elongate device substantially the same during the first interval;based on at least one of movement or user input during a second intervalof the plurality of intervals, adjust the property of the elongatedevice at a first rate during the second interval; and based on at leastone of movement or user input during a third interval of the pluralityof intervals, adjust the property of the elongate device at a secondrate that is greater than the first rate during the third interval. 2.The robotic system of claim 1, wherein the property includes a rigidityof the elongate device, and wherein the control system is configured toreduce the rigidity of the elongate device at the first rate during thesecond interval and to reduce the rigidity of the elongate device at thesecond rate during the third interval.
 3. The robotic system of claim 2,wherein the control system is configured to keep the rigiditysubstantially the same during the first interval based on retraction ofthe elongate device being less than a threshold.
 4. The robotic systemof claim 3, wherein the control system is configured to reduce therigidity of the elongate device at the first rate during the secondinterval and to reduce the rigidity of the elongate device at the secondrate during the third interval based on retraction of the elongatedevice being greater than the threshold.
 5. The robotic system of claim3, wherein the control system is configured to reduce the rigidity ofthe elongate device at the first rate during the second interval basedon a retraction velocity of the elongate device being less than a secondthreshold and to reduce the rigidity of the elongate device at thesecond rate during the third interval based on the retraction velocityof the elongate device being greater than the second threshold.
 6. Therobotic system of claim 2, wherein the control system is configured tokeep the rigidity substantially the same during the first interval basedon user input commanding the elongate device to retract less than athreshold.
 7. The robotic system of claim 6, wherein the control systemis configured to reduce the rigidity of the elongate device at the firstrate during the second interval and to reduce the rigidity of theelongate device at the second rate during the third interval based onuser input commanding the elongate device to retract more than thethreshold.
 8. The robotic system of claim 6, wherein the control systemis configured to reduce the rigidity of the elongate device at the firstrate during the second interval based on user input commanding theelongate device to retract at a velocity less than a second thresholdand to reduce the rigidity of the elongate device at the second rateduring the third interval based on user input commanding the elongatedevice to retract at a velocity greater than the second threshold. 9.The robotic system of claim 1, wherein the control system is configuredto adjust the property of the elongate device based on at least one of:an amount of retraction from a latched position, a velocity ofretraction, a duration of retraction, a total insertion depth, alocation as a percentage of current maximum insertion depth, a size of auser input, a speed of a user input, a velocity of a user input, aduration of a user input, or pressure on the control device.
 10. Therobotic system of claim 1, wherein the control system is configured toprioritize the monitored movement of the elongate device over themonitored user input.
 11. The robotic system of claim 1, wherein thecontrol system is configured to determine a mode for the elongate devicebased on at least one of the monitored movement or the monitored userinput.
 12. The robotic system of claim 11, wherein determination of themode includes operations to: determine an active mode based onretraction of the elongate device being less than a threshold; anddetermine a retraction mode based on retraction of the elongate devicebeing greater than the threshold.
 13. The robotic system of claim 12,wherein determination of the mode includes operations to: determine theretraction mode based on a retraction velocity of the elongate devicebeing greater than a second threshold.
 14. The robotic system of claim11, wherein determination of the mode includes operations to: determinean active mode based on the user input commanding retraction of theelongate device less than a threshold; and determine a retraction modebased on the user input commanding retraction of the elongate devicemore than the threshold.
 15. The robotic system of claim 14, whereindetermination of the mode includes operations to: determine theretraction mode based on the user input commanding a retraction velocitygreater than a second threshold.
 16. The robotic system of claim 14,wherein determination of the mode includes operations to: determine theactive mode based on the user input commanding advancement along aninsertion axis; and determine the active mode based on the user inputcommanding movement along a degree of freedom other than the insertionaxis without retraction along the insertion axis.
 17. The robotic systemof claim 1, wherein the manipulator assembly includes an insertion stageconfigured to drive a device body to which the elongate device iscoupled, and wherein the control system is further configured to monitorthe movement by monitoring movement of the device body along theinsertion stage.
 18. The robotic system of claim 1, wherein the controlsystem is further configured to: based on a rigidity of the elongatedevice, limit a retraction velocity of the elongate device in responseto the user input.
 19. The robotic system of claim 1, wherein thecontrol system is further configured to limit a retraction velocity ofthe elongate device based on a maximum rate of change of rigidity of theelongate device.
 20. A method comprising: monitoring movement of anelongate device; receiving user input commanding motion of the elongatedevice; determining a mode of operation based on at least one of themonitored movement or the received user input; and adjusting a propertyof the elongate device based on a profile associated with the mode ofoperation, wherein the adjusting the property of the elongate deviceincludes: maintaining the property of the elongate device substantiallythe same during a first interval; adjusting the property of the elongatedevice at a first rate during a second interval; and adjusting theproperty of the elongate device at a second rate that is different fromthe first rate during a third interval. 21-38. (canceled)